title: Increasing trends in primary NNRTI resistance among newly HIV-1-diagnosed individuals in Buenos Aires, Argentina.
abstract: OBJECTIVE
  Our objective was to estimate primary resistance in an urban setting in a developing country characterized by high antiretroviral (ARV) coverage over the diagnosed population and also by an important proportion of undiagnosed individuals, in order to determine whether any change in primary resistance occurred in the past five years.
  
  
  METHODS
  We carried out a multi-site resistance surveillance study according to WHO HIV resistance guidelines, using a weighted sampling technique based on annual HIV case reports per site.
  
  
  METHODS
  Blood samples were collected from 197 drug-naive HIV-1-infected individuals diagnosed between March 2010 and August 2011 at 20 HIV voluntary counselling and testing centres in Buenos Aires. Clinical records of enrolled patients at the time of diagnosis were compiled. Viral load and CD4 counts were performed on all samples. The pol gene was sequenced and the resistance profile determined. Phylogenetic analysis was performed by neighbour-joining (NJ) trees and bootscanning analysis.
  
  
  RESULTS
  We found that 12 (7.9%) of the 152 successfully sequenced samples harboured primary resistance mutations, of which K103N and G190A were the most prevalent. Non-nucleoside reverse transcriptase inhibitors (NNRTI) resistance mutations were largely the most prevalent (5.9%), accounting for 75% of all primary resistance and exhibiting a significant increase (p=0.0072) in prevalence during the past 10 years as compared to our previous study performed in 1997-2000 and in 2003-2005. Nucleoside reverse transcriptase inhibitor (NRTI) and protease inhibitor primary resistance were low and similar to the one previously reported.
  
  
  CONCLUSIONS
  Levels of primary NNRTI resistance in Buenos Aires appear to be increasing in the context of a sustained ARV coverage and a high proportion of undiagnosed HIV-positive individuals.
authors.affiliation: Instituto de Investigaciones Biomédicas en Retrovirus y SIDA (INBIRS), Universidad de Buenos Aires-CONICET, Buenos Aires, Argentina.
authors.forename: Nahuel
authors.initials: N
authors.lastname: Rodriguez-Rodrigues
authors.forename: Adriana
authors.initials: A
authors.lastname: Duran
authors.forename: María Belen
authors.initials: MB
authors.lastname: Bouzas
authors.forename: Ines
authors.initials: I
authors.lastname: Zapiola
authors.forename: Marcelo
authors.initials: M
authors.lastname: Vila
authors.forename: Debbie
authors.initials: D
authors.lastname: Indyk
authors.forename: Emiliano
authors.initials: E
authors.lastname: Bissio
authors.forename: Horacio
authors.initials: H
authors.lastname: Salomon
authors.forename: Dario A
authors.initials: DA
authors.lastname: Dilernia
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001118:Argentina / Q000453:epidemiology; D024882:Drug Resistance, Viral; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D015994:Incidence; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017422:Sequence Analysis, DNA; D014505:Urban Population; D055815:Young Adult; D054302:pol Gene Products, Human Immunodeficiency Virus / Q000235:genetics
chemical_list: D019380:Anti-HIV Agents; D054302:pol Gene Products, Human Immunodeficiency Virus
keywords: HIV; NNRTI; newly diagnosed; primary drug resistance; trend